When the alkali metals are cut, they initially appear shiny grey but quickly become dull and white as they react with oxygen in the air. This is known as tarnishing. Sodium tarnishes more quickly ...

Many metals react with oxygen to form metal oxides. Potassium and sodium are soft metal which are easily cut exposing a shiny surface which changes to dull rapidly. The change from shiny to dull ...

The atom with eight protons in its nucleus (atomic number 8) is oxygen. Each energy level ... and hydrogen gas which ignites. The reaction of the potassium with water is similar to the reaction of ...